Various technologies have been developed that provide navigation-related and map-related services. For example, vehicle navigation systems can determine where a person or a vehicle is located and provide directions to travel to a desired destination. Other navigation-related services may provide other information to mobile users based on the location. Also, internet sites provide maps, directions for traveling to a desired destination from a specified starting point, and other map-related services.
In order to provide these and other map-related functions and features, navigation systems use geographic data. The geographic data may be in the form of one or more geographic databases that include data representing physical features in the geographic region. The geographic data may be referenced to a variety of coordinate systems.
Some geographic entities are naturally described using existing referencing formats but other geographic entities such as closed area geometries may be computationally intensive for navigation systems.